Preheat oven to 350°F and grease an 8×8 or 9×13 pan.
Mix brown sugar, corn syrup, ¼ cup melted butter, vanilla, eggs, and salt.
Fold in half the pecans, pour mixture into pan.
Sprinkle dry cake mix evenly on top—do not stir.
Drizzle remaining ¼ cup melted butter over the cake mix.
Top with remaining pecans.
Bake 30–35 minutes until golden and set. Let cool for 10 minutes before serving.